1. Field of the Invention
The present invention relates to an exhaust pipe structure for a motorcycle wherein an exhaust pipe branches halfway.
2. Description of Background Art
A structure is known wherein an exhaust pipe, connected to an exhaust port of an internal combustion engine, is made to branch halfway and be connected to left and right mufflers. See, for example, Japanese Patent Laid-Open No. 2010-100224.
In Japanese Patent Laid-Open No. 2010-100224, the branching part of the exhaust pipe is provided on the rear side relative to a cylinder head of the internal combustion engine. Furthermore, on the immediate downstream side of the branching part, one exhaust pipe drastically curves in such a manner so as to avoid a rear shock absorber unit. In addition, the other exhaust pipe extends substantially on an extension of the exhaust pipe on the upstream side of the branching part. Therefore, in the one exhaust pipe, the exhaust flow is biased toward the outer circumferential side in the pipe and the airflow resistance increases, which suppresses the passing of the exhaust air. Accordingly, there is a problem that most of the exhaust air before the branching flows into the other exhaust pipe.